1. Field of the Invention
The present invention relates to a wetting/inking mechanism for offset printing presses that have a plurality of applicator rolls which correspond to a plate cylinder, the first and second applicator rolls of which, when viewed in the direction of rotation of the plate cylinder, are connected to one another by means of an ink distributing roller. The printing press also has a dip roller which is located in a wetting agent tank, which is in contact which a dosing roller, and which is mounted so that it can move into contact with the first applicator roll.
The disadvantage of known wetting/inking mechanisms which are configured in this manner is that, in all the different inking processes, the wetting agent is transported to the first applicator roll, seen in the direction of rotation of the plate cylinder, and by means of contact between the first ink applicator roll and the distributing roller, ink and wetting agent are always being transferred to the printing plate. As a result, build-up and overflow of ink and/or wetting agent can occur.
Also, the present invention relates to a roller in a printing unit of a rotary printing machine in which the entire outer cylindrical surface of the roller has a uniform roughness.
2. Background Information
German Patent No. 31 46 223 describes a wetting/inking mechanism for offset printing presses in which there are a total of five applicator rolls for the plate cylinder, the first and second rolls of which, seen in the direction of rotation of the plate cylinder, are connected by means of an intermediate roller. In this device, the wetting mechanism works together with the first applicator roll. The large number of applicator rolls utilized in this design clearly increases its manufacturing costs. German Laid Open Patent Appln. No. 29 32 105 describes a wetting/inking mechanism in which the first applicator roll, seen in the direction of rotation of the plate cylinder, the distributing roller working together with it, and the dip roller immersed in the wetting agent tank, are mounted in a separate frame. By pivoting this separate frame, the distributing roller can be pivoted toward or away from the second applicator roll. This design already makes possible a separation between the wetting mechanism and the inking mechanism for the processing of certain jobs. However, the design is significantly complex and expensive to implement.
German Patent Publication Published for Opposition Purposes No. 24 32 576 describes rollers having rough outer cylindrical surfaces. However, these rollers are used as wetting distributor rollers in a wetting unit of an offset printing machine. These wetting distributor rollers are used to uniformly distribute wetting medium film. The roughness of the outer cylindrical surface of the wetting distributor roller is designed to prevent the wetting medium from accumulating before the point at which the wetting distributor roller contacts other rollers cooperating therewith. Therefore, the rough outer cylindrical surface of the wetting distributor roller is employed only to ensure a continuous wetting-medium supply, to achieve a uniform wetting-medium film.